[TangerineSDR] TangerineSDR Digest, Vol 12, Issue 24

Tue Mar 31 12:06:11 EDT 2020

Hi All-

I will add a comment if it is of interest, that I wrote some code a while back in python that directly calculates the magnetic field using the IGRF coefficients and derivatives (useful in a ray tracer).  If you guys want that, I could package it up and send it over to anyone interested.  

Thanks,
Steve

------------------------------------------------------------
Stephen R. Kaeppler, Ph.D.
Assistant Professor
Department of Physics and Astronomy
Clemson University
Clemson, SC 29634
Email: skaeppl at clemson.edu
Phone: 864-656-4275
Web: http://science.clemson.edu/kaeppler/
Amateur Radio Callsign: AD0AE
------------------------------------------------------------

On 3/31/20, 12:00 PM, "TangerineSDR on behalf of tangerinesdr-request at lists.tapr.org" <tangerinesdr-bounces at lists.tapr.org on behalf of tangerinesdr-request at lists.tapr.org> wrote:

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Today's Topics:

   1. Notes from PSWS / TangerineSDR call of 03-30-2020 (Tom McDermott)
   2. Re: Notes from PSWS / TangerineSDR call of 03-30-2020
      (Phil Erickson)
   3. Re: Notes from PSWS / TangerineSDR call of 03-30-2020
      (nafrissell at gmail.com)

----------------------------------------------------------------------

Message: 1
Date: Mon, 30 Mar 2020 19:04:47 -0700
From: Tom McDermott <tom.n5eg at gmail.com>
To: TAPR TangerineSDR Modular Software Defined Radio
	<tangerinesdr at lists.tapr.org>
Subject: [TangerineSDR] Notes from PSWS / TangerineSDR call of
	03-30-2020
Message-ID:
	<CACO3nRRtu9NJvau7BWe7u3KJBfMUNkHHtyup6U=VPMKipmoamQ at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Notes from PSWS / TangerineSDR call of 03-30-2020
1. Bill has started posting the PSWS / TangerineSDR software to
https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_AB4EJ-2D1_TangerineSDR-2Dnotes&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=lWkOPWOwCC3ZC6yAFUcncIUG1VG9um59rVbpETbfQRY&e= 

2. Kp is determined by a network of magnetometers. This is useful
in predicting propagation disturbances. During normal conditions:
  At the poles the vertical component should be about 60,000 nT and the
  horizontal component near zero. At the equator the horizontal component
  should be about 30,000 nT and the vertical component near zero.

3. Discussion on magnetometer calibration: how often do they need to be
calibrated, and how would this be accomplished?

4. International Geomagnetic Reference Field (IGRFG) model profile
parameters provides long term estimates of magnetic field by
lat/long/height and year:
https://urldefense.proofpoint.com/v2/url?u=https-3A__ccmc.gsfc.nasa.gov_modelweb_models_igrf-5Fvitmo.php&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=nrsmIy4XRQ1oeO9QLC-y4yZ-PMsSC3F5RGAXQqxulDI&e= 

-- Tom, N5EG
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------------------------------

Message: 2
Date: Mon, 30 Mar 2020 23:40:57 -0400
From: Phil Erickson <phil.erickson at gmail.com>
To: TAPR TangerineSDR Modular Software Defined Radio
	<tangerinesdr at lists.tapr.org>
Subject: Re: [TangerineSDR] Notes from PSWS / TangerineSDR call of
	03-30-2020
Message-ID:
	<CAAZaqEvuOWLKtH0R0MQmxooc1CxAJoUm_c_VmsLjsasjo3eoEA at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Hi all,

  Sorry I missed the call.  There is a typo: the field model is IGRF, not
IGRFG.

  IGRF is provided by a series of spherical harmonic coefficients.  These
are marked for any 5 year interval either as intermediate (IGRF),
definitive (DGRF), or predictive (for the current 5 year interval; uses
secular change estimates).  Usually the coefficients come out every 5
years, but the field was changing so fast that the last update came early
in 2019 instead of 2020.  A simple code, often in FORTRAN, calculates the
field given location and epoch (time).

73
Phil W1PJE

On Mon, Mar 30, 2020 at 10:28 PM Tom McDermott via TangerineSDR <
tangerinesdr at lists.tapr.org> wrote:

> Notes from PSWS / TangerineSDR call of 03-30-2020
> 1. Bill has started posting the PSWS / TangerineSDR software to
> https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_AB4EJ-2D1_TangerineSDR-2Dnotes&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=lWkOPWOwCC3ZC6yAFUcncIUG1VG9um59rVbpETbfQRY&e= 
>
> 2. Kp is determined by a network of magnetometers. This is useful
> in predicting propagation disturbances. During normal conditions:
>   At the poles the vertical component should be about 60,000 nT and the
>   horizontal component near zero. At the equator the horizontal component
>   should be about 30,000 nT and the vertical component near zero.
>
> 3. Discussion on magnetometer calibration: how often do they need to be
> calibrated, and how would this be accomplished?
>
> 4. International Geomagnetic Reference Field (IGRFG) model profile
> parameters provides long term estimates of magnetic field by
> lat/long/height and year:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__ccmc.gsfc.nasa.gov_modelweb_models_igrf-5Fvitmo.php&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=nrsmIy4XRQ1oeO9QLC-y4yZ-PMsSC3F5RGAXQqxulDI&e= 
>
> -- Tom, N5EG
>
>
> --
> TangerineSDR mailing list
> TangerineSDR at lists.tapr.org
> https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.tapr.org_mailman_listinfo_tangerinesdr-5Flists.tapr.org&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=BuRwEim8Ya-UvGU9OrMB8VnG58qKn1rI8YUUWXPVZ7o&e= 
>

-- 
----
Phil Erickson
phil.erickson at gmail.com
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------------------------------

Message: 3
Date: Tue, 31 Mar 2020 09:29:29 -0400
From: <nafrissell at gmail.com>
To: "'TAPR TangerineSDR Modular Software Defined Radio'"
	<tangerinesdr at lists.tapr.org>
Subject: Re: [TangerineSDR] Notes from PSWS / TangerineSDR call of
	03-30-2020
Message-ID: <00e701d60760$686f0750$394d15f0$@gmail.com>
Content-Type: text/plain; charset="utf-8"

Hi all,

Also, I mentioned last night the Guide for Magnetic Measurements and Observatory Practice from IAGA (International Association of Geomagnetism and Aeronomy). Here is the link:

https://urldefense.proofpoint.com/v2/url?u=http-3A__www.iaga-2Daiga.org_data_uploads_pdf_guides_iaga-2Dguide-2Dobservatories.pdf&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=i_orQ6M6n3ELv1Pu22ga77aQA-W-bz6ww28ygQ9Itus&e= 

IAGA publishes a number of guides that may be of interest. Here is the complete list:

https://urldefense.proofpoint.com/v2/url?u=http-3A__www.iaga-2Daiga.org_publications_guides_&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=NEdN5lXzg3QZZbhR3MmAmv9tLEZiuuT0zsh0KaaQcSs&e= 

The IAGA guide is a bit old (1996). So here the current technical reference from intermagnet.org: https://urldefense.proofpoint.com/v2/url?u=https-3A__intermagnet.org_publications_intermag-5F4-2D6.pdf&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=Hb3J9atPpBms0vUyTC2wtPV5DGIISXl8i_VDoM0xkIc&e= 

I think the IAGA guide is a bit ?friendlier? and perhaps more comprehensive, but it is good to have a more current reference as well.

Also, since this is a ham radio group, it is good to remember that ground magnetometer measurements have a strong connection with radio propagation. Most people here are familiar with the Kp index, which is used as a global indicator of geomagnetic storms. One of the largest effects of a geomagnetic storm is an extended depletion of ionospheric densities, which leads to poor propagation on the higher HF bands. The Kp index actually comes from measurements of a network of 13 ground magnetometer stations located around the globe (but not evenly spaced!). See https://urldefense.proofpoint.com/v2/url?u=http-3A__blog.aurorasaurus.org_-3Fp-3D187&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=DsZLrC1CgTLbsUtgx6gUtnRtO6Jw0D5Pqh1PsQ94pqk&e=  for a nice description. For a more ham radio perspective, see https://urldefense.proofpoint.com/v2/url?u=https-3A__www.arrl.org_files_file_Technology_tis_info_pdf_0209038.pdf&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=dBfJtLoM-WPvH33Gr4Ie53Dz3tytFyAHNsPb9b-w6wM&e= .

73 de Nathaniel W2NAF

From: TangerineSDR <tangerinesdr-bounces at lists.tapr.org> On Behalf Of Phil Erickson via TangerineSDR
Sent: Monday, March 30, 2020 11:41 PM
To: TAPR TangerineSDR Modular Software Defined Radio <tangerinesdr at lists.tapr.org>
Cc: Phil Erickson <phil.erickson at gmail.com>
Subject: Re: [TangerineSDR] Notes from PSWS / TangerineSDR call of 03-30-2020

Hi all,

  Sorry I missed the call.  There is a typo: the field model is IGRF, not IGRFG.

  IGRF is provided by a series of spherical harmonic coefficients.  These are marked for any 5 year interval either as intermediate (IGRF), definitive (DGRF), or predictive (for the current 5 year interval; uses secular change estimates).  Usually the coefficients come out every 5 years, but the field was changing so fast that the last update came early in 2019 instead of 2020.  A simple code, often in FORTRAN, calculates the field given location and epoch (time).

73

Phil W1PJE

On Mon, Mar 30, 2020 at 10:28 PM Tom McDermott via TangerineSDR <tangerinesdr at lists.tapr.org <mailto:tangerinesdr at lists.tapr.org> > wrote:

Notes from PSWS / TangerineSDR call of 03-30-2020

1. Bill has started posting the PSWS / TangerineSDR software to
https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_AB4EJ-2D1_TangerineSDR-2Dnotes&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=lWkOPWOwCC3ZC6yAFUcncIUG1VG9um59rVbpETbfQRY&e= 

2. Kp is determined by a network of magnetometers. This is useful
in predicting propagation disturbances. During normal conditions:

  At the poles the vertical component should be about 60,000 nT and the
  horizontal component near zero. At the equator the horizontal component
  should be about 30,000 nT and the vertical component near zero.

3. Discussion on magnetometer calibration: how often do they need to be calibrated, and how would this be accomplished?

4. International Geomagnetic Reference Field (IGRFG) model profile parameters provides long term estimates of magnetic field by lat/long/height and year:
https://urldefense.proofpoint.com/v2/url?u=https-3A__ccmc.gsfc.nasa.gov_modelweb_models_igrf-5Fvitmo.php&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=nrsmIy4XRQ1oeO9QLC-y4yZ-PMsSC3F5RGAXQqxulDI&e= 

-- Tom, N5EG

-- 
TangerineSDR mailing list
TangerineSDR at lists.tapr.org <mailto:TangerineSDR at lists.tapr.org> 
https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.tapr.org_mailman_listinfo_tangerinesdr-5Flists.tapr.org&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=n5dABjqqUu235-fKc_tfEE359SMgtk5rJZFy5xGDvRg&m=iHBHDPMZFfmy81bJ6XDPJKGs96ObWI-b0-5SNatURTg&s=BuRwEim8Ya-UvGU9OrMB8VnG58qKn1rI8YUUWXPVZ7o&e= 

-- 

----
Phil Erickson
phil.erickson at gmail.com <mailto:phil.erickson at gmail.com> 

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End of TangerineSDR Digest, Vol 12, Issue 24
********************************************